System and method for providing passive haptic feedback

ABSTRACT

Systems and methods for providing passive haptic feedback are described. Embodiments of the present invention comprise an actuator for bringing a manipulandum and braking surface into contact and thereby providing a resistance. The manipulandum includes scroll wheels, scroll drums, linear sliders and similar user input devices. The actuator may be, for example, electromagnetic or piezo-electric. An embodiment of the present invention may include a processor in communication with the actuator for providing the haptic effects.

RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional ApplicationNo. 60/399,883 filed Jul. 31, 2002, the entire disclosure of which isincorporated herein by reference.

NOTICE OF COPYRIGHT PROTECTION

[0002] A section of the disclosure of this patent document and itsfigures contain material subject to copyright protection. The copyrightowner has no objection to the facsimile reproduction by anyone of thepatent document, but otherwise reserves all copyright rights whatsoever.

FIELD OF THE INVENTION

[0003] The present invention generally relates to providing hapticfeedback to a manipulandum. The present invention more particularlyrelates to providing passive haptic feedback to user interface devices.

BACKGROUND

[0004] Electronic device manufacturers are constantly striving toproduce a rich interface for users. Conventional devices utilize visualand auditory cues to provide feedback to a user. In some interfacedevices, kinesthetic feedback (such as, without limitation, active andpassive force feedback), and/or tactile feedback (such as, withoutlimitation, vibration, texture, and heat), is also provided to the user,more generally known collectively as “haptic feedback.” Haptic feedbackprovides additional cues that enhance and simplify the user interface.

[0005] A device may incorporate a variety of technologies for providinghaptic feedback, including both active and passive devices. Activehaptic feedback devices, including, for example, motors, add energy to asystem; passive devices, such as brakes, remove energy from the system.

[0006] Conventional passive haptic actuators utilize magnetic particlebrakes, magnetorheologic or electrorheologic brakes, or magnetic(non-friction) brakes. Each of these conventional approaches suffersfrom disadvantages. These conventional devices are expensive anddifficult to produce. They are also larger than is practical forimplementation in small, handheld devices, such as cell phones, personaldigital assistants, and the like.

[0007] Conventional magnetic particle brakes utilize a powder comprisingparticles of a magnetic material. When a current is applied, theparticles line up and cause the powder to expand. Rheologic fluid brakesutilize a fluid that changes viscosity when a current is applied. Thesetypes of devices are expensive because of the cost of the materials andbecause of the need to retain the fluid within the device.

[0008] A magnetic brake generates a magnetic field, and when a piece ofmetal passes through the magnetic field, an anti-current is generated,causing a resistance to movement of the metal. Conventional magneticbrakes require the metal to be moving at high speed to be effective.Thus, these devices are not practical for relatively slow moving userinterface elements.

SUMMARY

[0009] Embodiments of the present invention provide passive hapticfeedback to manipulanda. One embodiment of the present inventioncomprises a manipulandum, a brake surface and an actuator incommunication with either the manipulandum or the brake surface. Theactuator causes the brake surface and manipulandum to come in tocontact. The resulting friction between the manipulandum and brakesurface causes a resistance, which can be controlled to deliver hapticeffects to a user of the manipulandum.

[0010] Embodiments may utilize a variety of manipulanda, such as ascroll wheel, scroll drum, and linear slider. Embodiments also mayutilize a variety of actuators, such as electromagnetic andpiezo-electric actuators. In an electronic device incorporating oneembodiment of the present invention, the manipulandum is incommunication with a position sensor. The manipulandum and actuator arein communication with a controller, which receives position signals fromthe manipulandum and provides haptic feedback signals to the actuator.Embodiments of the present invention may be utilized by a broad array ofdevices, including cell phones, personal digital assistants, cameras,camcorders, MP3 players, and other electronic devices.

[0011] Further details and advantages of embodiments of the presentinvention are set forth below.

BRIEF DESCRIPTION OF THE FIGURES

[0012] These and other features, aspects, and advantages of the presentinvention are better understood when the following Detailed Descriptionis read with reference to the accompanying drawings, wherein:

[0013]FIG. 1 illustrates a personal digital assistant incorporating oneembodiment of the present invention;

[0014]FIG. 2A is a cutaway diagram of a manipulandum and haptic actuatorin one embodiment of the present invention;

[0015]FIG. 2B is a cutaway diagram of the manipulandum of FIG. 2A in anengaged state in one embodiment of the present invention;

[0016]FIG. 3A is a cutaway diagram of a scroll drum manipulandum andhaptic actuator in one embodiment of the present invention;

[0017]FIG. 3B is an exploded view of the manipulandum and actuator ofFIG. 3A in one embodiment of the present invention;

[0018]FIG. 4 is a diagram illustrating a conical or tapered brakingsurface and piezo-electric actuation in one embodiment of the presentinvention;

[0019]FIG. 5 is a diagram illustrating a scroll drum manipulandumincorporating passive feedback in one embodiment of the presentinvention;

[0020]FIG. 6A is a diagram of a linear slider in an embodiment of thepresent invention;

[0021]FIG. 6B is a diagram illustrating an end view of the slider ofFIG. 6A in one embodiment of the present invention;

[0022]FIG. 7 is a block diagram, illustrating one embodiment of apassive feedback device according to the present invention;

[0023]FIG. 8 is a flowchart, illustrating a process for address entrynavigation on a cell phone incorporating an actuator according to thepresent invention; and

[0024]FIG. 9 is a flowchart, illustrating a process of navigating emailon a personal digital assistant (PDA) utilizing an embodiment of thepresent invention.

DETAILED DESCRIPTION

[0025] Embodiments of the present invention provide passive hapticfeedback systems and methods, and applications thereof, utilizingfrictional braking. Embodiments include devices, comprising amanipulandum, a brake surface, and an actuator for bringing themanipulandum and brake surface into contact.

[0026] Referring now to the drawings in which like numerals indicatelike elements throughout the several figures, FIG. 1 illustrates apersonal digital assistant incorporating one embodiment of the presentinvention. The personal digital assistant (PDA) 100 shown in FIG. 1includes a display screen 102 and several manipulanda, interfaceelements that a user of the PDA 100 can manipulate. The manipulandainclude a plurality of buttons 104 a, 104 b, 103 c, 104 d and a scrollwheel 106. In one embodiment, the user utilizes the buttons 104 a-d toaccess specific application, such as an address book. Once the user hasaccessed the address book application, the user utilizes the scrollwheel 106 to navigate through the various elements of the userinterface, such as menus or a list of names contained in the electronicaddress book. The embodiment shown in FIG. 1 provides haptic feedback tothe scroll wheel 106 to enhance the user's interaction with the PDA 100.

[0027] A device according to the present invention may provide hapticfeedback in various physical mechanisms, such as the scroll wheel (106)shown in FIG. 1. FIG. 2A is a cutaway diagram of a manipulandum andhaptic actuator in one embodiment of the present invention. In theembodiment shown in FIG. 2A, the manipulandum is a scroll wheel 202. Thescroll wheel 202 may be, for example, the scroll wheel shown in the PDA(100) of FIG. 1.

[0028] At its center, the scroll wheel 202 is connected to a shaft 204.The scroll wheel 202 and shaft 204 rotate around a common axis. Abraking surface 206 in the form of a disk is mounted on the shaft 204 sothat the braking surface 206 is moveable towards the scroll wheel 202parallel to the shaft 204. The braking surface 206 in FIG. 2A is notfree to rotate (although in other embodiments it may rotate). Thebraking surface 206 in FIG. 2A contains an electromagnet 208. When theelectromagnet 208 receives a current, it develops a magnetic attractiveforce, and the magnetic attractive force moves the braking surface 206and scroll wheel 202 into contact. The contact between theses elementscauses a resistance to movement of the scroll wheel 202. The resistancemay cause the scroll wheel 202 to stop or may exert a force that theuser can overcome. In another embodiment, a spring mounted between thebrake and the scroll wheel causes the two elements to separate when theelectromagnet is not energized. FIG. 2B illustrates the scroll wheel 202and the braking surface 206 in contact with one another. A controller,such as a processor, that controls the application of current to theelectromagnet 208 is capable of generating a variety of haptic effects.For example, the controller can create effects, such as detents, betweenentries in the address book application described with reference toFIG. 1. The controller may create additional effects as well, including,for example, bumps and stops.

[0029]FIG. 3A is a cutaway diagram of a scroll drum 300 in anotherembodiment of the present invention. The scroll drum 360 shown is aself-contained haptic actuator. A cylinder 302 is attached to a firstshaft 304 such that the cylinder 302 is capable of rotating. Inside thecylinder 302 are a plurality of braking surfaces 306 a,b. In theembodiment shown, the braking surfaces 306 are fixed so as not to rotatein relation to the cylinder 302. A cylindrical electromagnet 308 ismounted between the braking surfaces 306 and a second, non-rotatingshaft 310. When current is supplied to the electromagnet 308, thebraking surfaces 306 are forced away from the electromagnet 306 and intocontact with the cylinder 302, causing a resistance to rotation of thecylinder 302.

[0030]FIG. 3B is an exploded view of the internal structure of thescroll drum 300 shown in FIG. 3A. The braking surfaces 306 include acurved surface to contact a greater inside surface area of the rotatingcylinder (not shown in FIG. 3B). The braking surfaces 306 include a tab312 on either end. The tab 312 fits in a slot 314 in non-rotating shaft310. When the electromagnet 308 has no current flowing to it, thebraking surfaces 306 are positioned in the slot 314 at a position inclose proximity to the electromagnet 308. When a current is supplied tothe electromagnet 308, the braking surfaces 306 are forced away from theelectromagnet 308 and into contact with the rotating cylinder (notshown). When the braking surfaces 308 and rotating cylinder 302 are incontact, the user feels a resistive force when attempting to rotate thecylinder 302.

[0031]FIG. 4 is a diagram illustrating another embodiment of the presentinvention. The embodiment shown in FIG. 4 utilizes a piezo-electricactuation to provide braking forces to a scroll wheel 402. In apiezo-electric actuator, a relatively high voltage is applied to apiezo-ceramic, causing the crystals to elongate and thereby chaining theshape of the material. Typically, that material shape change isrelatively small and some type of amplification is utilized to provide amechanical force.

[0032] Referring again to FIG. 4, the scroll wheel 402 is mounted on ashaft 404 such that the scroll wheel 402 is able to rotate. The shaft404 is connected to a housing 406. The scroll wheel 402 includes aconical indentation 408 on the side opposite the shaft 406. Alsoattached to the housing is a piezo-ceramic material 410 mounted to abase 412, which is further mounted to the housing 406. In the embodimentshown, the base 412 is a thin brass sheet. The piezo-ceramic material410 is attached to the base 412 at the edges of the piezo-ceramic 410.The piezo-ceramic material 410 covers approximately 50-70% of the uppersurface area of the base 412. Alternatively, the piezo-ceramic materialcan cover less than approximately 50% and/or more than approximately70%. When current is supplied to the piezo-ceramic 410, the materialattempts to stretch. However, since the edges are secured, the center ofthe piezo-ceramic 410 is forced away from the base 412, providing arelatively large displacement.

[0033] A lever 414 is connected to the piezo-ceramic material 410. Thelever 414 includes a flexure 416 at or near a midpoint of its length.The flexure 416 is connected to a fulcrum 418 so that the lever 414 canrotate about the flexure 416. A conical or tapered braking surface 420is attached to the lever 414 at the end distal from the piezo-ceramic420. The braking surface in the embodiment shown, the braking surface420 is formed in a shape complementary to the shape of the conicalindentation 408 of the scroll wheel 402. When current is suppliedpiezo-ceramic material 410, forcing away from the base 412, the lever414 is also forced away from the base 412. This movement causes thelever 414 to rotate about the flexure 416, further causing the conicalbraking surface 420 into contact with the inside surface of the conicalindentation 408 in the scroll wheel 402. When the braking surface 420and scroll wheel 402 are in contact, the user feels a resistance torotation of the scroll wheel 402. The resistance is proportional to thecurrent fed to the piezo-electric material 410.

[0034]FIG. 5 is a diagram of a scroll drum manipulandum incorporatingpassive feedback in an embodiment of the present invention. Themanipulandum 500 shown includes a scroll drum 502 mounted to a pair ofsupports 504 a, b such that scroll drum 502 is able to rotate. Supports504 a,b pivot about an axis 506 a,b. An electromagnet 508, a solenoid inthe embodiment shown, is also connected to supports 506 a,b with a shaft510. The shaft passes through a hole in an end portion 512 a,b of eachsupport 504 a,b. When the electromagnet 508 is energized, it attractsend portions 512 a,b towards it. The movement of the end portions 512a,b causes the supports 504 a,b to pivot about their axis 506 a,b andexert a force on the ends of the scroll drum 502. This force causes aresistance to rotation of the scroll drum 502. The supports 512 a,bprovide a lever system that serves to multiply the force provided by theelectromagnet 508.

[0035]FIG. 6A is a diagram of another embodiment of the presentinvention. In the embodiment shown in FIG. 6A, a linear slider 600includes an open frame slide potentiometer. The slider 600 includes acentral core 602 with a lead at each end 604, 606 connected to a winding608 around the central core 602. The handle 610 of the slider 600 fitsaround the central core 602. The handle 610 is connected to a third lead612 such that when the handle 610 moves, the lead 612 moves and changesthe resistance present between leads 604 and 612. The slider 600 alsoincludes a rectangular braking surface 614 and an electromagnet 616.When the electromagnet 616 is energized, it repels the braking surface614, causing the braking surface 614 to come into contact with theslider handle 610 and provide a resistive force. FIG. 6B is an end viewof the slider 600 shown in FIG. 6A.

[0036]FIG. 7 is a block diagram, illustrating one embodiment of apassive feedback device according to the present invention. In theembodiment shown, the passive feedback device 700 includes amanipulandum 702. The manipulandum 502 may comprise one of themanipulanda discussed in relation to FIGS. 1-7 or various other types ofmanipulanda. The device 700 also includes an actuator 704, such as anelectromagnetic or piezo-electric brake. The manipulandum 702 andactuator 704 are in communication with a processor 706. The processor706 receives sensor information from the manipulandum 702, performscontrol algorithms, and provides feedback control signals to theactuator 704.

[0037] Processors can include, for example, digital logical processorscapable of processing input, execute algorithms, and generate output asnecessary to create the desired tactile sensations in the input devicein response to the inputs received from that input device. Suchcontrollers may include a microprocessor, an Application SpecificIntegrated Circuit (ASIC), and state machines. Such processors include,or may be in communication with, media, for example computer readablemedia, which stores instructions that, when executed by the processor,cause the processor to perform the steps described herein as carriedout, or assisted, by a processor. Embodiments of computer-readable mediainclude, but are not limited to, an electronic, optical, magnetic, orother storage or transmission device capable of providing a processor,such as the processor in a web server, with computer-readableinstructions. Other examples of suitable media include, but are notlimited to, a floppy disk, CD-ROM, magnetic disk, memory chip, ROM, RAM,ASIC, configured processor, all optical media, all magnetic tape orother magnetic media, or any other medium from which a computerprocessor can read. Also, various other forms of computer-readable mediamay transmit or carry instructions to a computer, including a router,private or public network, or other transmission device or channel.

[0038] The device also includes an input/output (I/O) port 708, such asa game port, for performing bi-directional communication with externaldevices utilizing an embodiment of the present invention. In theembodiment shown, the device 500 receives power from an external powersupply 710. In other embodiments, power may be supplied through the I/Oport 708 or by utilizing an internal power supply. Various embodimentsmay utilize additional components as well, such as an amplifier toamplify signals to the actuator.

[0039] Embodiments of the present invention may utilize various otherpassive actuators as well. For example, in one embodiment, a hybridactuator provides passive effects. In such an embodiment, a motor incommunication with a manipulandum is short-circuited or set up to act asa generator, causing a resistance. If the motor is set up as agenerator, then during certain braking effects and during dampingeffects, the motor can generate current back to the power supply.

[0040]FIG. 8 is a flowchart illustrating a process for address entrynavigation on a cell phone incorporating an actuator according to thepresent invention. The user first utilizes an interface element on thecell phone to select the address book application 802. The address bookdisplays a list of contact names. The user uses a scroll wheel on thecell phone to navigate to the next entry in the address book 804. Forexample, the user could use the scroll wheel of FIGS. 2A and 2B or thescroll drum of FIGS. 3A and 3B. The control application determineswhether or not the next entry is a favorite 806. If the entry is afavorite, the actuator provides a bump effect 808 and the process ends810. For example, in the actuator shown in FIG. 3A, a processorexecuting the control application sends a signal to the electromagnet(308), which causes the brake surface (306 a,b) to move into contactwith the scroll drum (302). The brake surface may comprise a disk,rectangle, or any other shape. Also, the brake surface may come intodirect or indirect contact with the manipulandum. For example, in oneembodiment, the brake surface contacts the shaft of the scroll drum(302), causing resistance in turning the scroll drum (302). The durationand force that the actuator applies depend on the signal that theprocessor generates. The processor determines the signal based upon analgorithm stored in a computer-readable medium.

[0041] If the entry is not a favorite, the application determineswhether the first letter of the next entry is the same as the firstletter of the current entry 812. If so, the actuator provides a softdetent effect 814. If the first letter of the entries is different, theactuator provides a hard detent effect 816. By differentiating betweenthe various entries in this manner, an embodiment of the presentinvention provides a richer interface than is available in conventionaldevices.

[0042]FIG. 9 is a flowchart illustrating a process of navigating emailon a personal digital assistant (PDA) utilizing an embodiment of thepresent invention. The method shown in illustrated in FIG. 9 isdescribed with reference to PDA (100) shown in FIG. 1. The PDA (100)includes a scroll wheel (106). For example, the scroll wheel (106) maybe the scroll wheel of FIGS. 2A and 2B or the scroll drum of FIGS. 3Aand 3B. The user of the PDA (100) receives an email 902. The userutilizes an interface device, such as button (104), to open the email904. Using the scroll wheel (106), the user scrolls to the bottom of theemail displayed on the PDA screen (102) 906. The PDA screen (102) may ormay not be large enough to display the email. If the email is longerthan the visible portion of the screen (102) 908, the actuator incommunication with the scroll wheel (106) causes a detent effect bycreating a resistance on the scroll wheel (106) over a short interval oftime 910. The user can overcome the effect by continuing to scroll downthrough the email using the scroll wheel (102). The effect provides anindicator to the user that the user is scrolling beyond the visibleportion of the email message. If the email is not longer than thevisible portion of the screen (102), the actuator causes a stop effect,a strong resistance to further movement of the scroll wheel (106) 912.Once the effect has been provided, the process ends 914. Various othertypes of effects may be utilized. For example, in one embodiment, theactuator provides a “bump” when the end of the email is reached. If theuser continues to scroll past the bump, the application displays thenext email in the folder the user is currently viewing.

[0043] Embodiments of the present invention may be incorporated into abroad array of devices. For example, a cell phone may incorporate ascroll drum according to this invention for use in navigating a menustructure. A television remote control may also incorporate anembodiment of the present invention for channel navigation, volumecontrol, and other related functions. Similarly, an audio componentremote control may utilize an embodiment for volume control or otheraudio control. A laptop computer may utilize an embodiment fornavigation, volume control, or any other function utilizing a scrollwheel, scroll drum, linear slider, or similar user interface device.PDA's, handheld navigation, and handheld email appliances may alsobenefit from utilizing an embodiment of the present invention.

[0044] A camera utilizes an embodiment of the present invention for usercontrol of the focus, f-stop, menu navigation, and other camera-relatedfunctions. Since the effects provided by the actuator are programmable,one manipulandum may be utilized to perform many or all of the functionson the camera. A video recorder may utilize an embodiment of the presentinvention to provide functions such as shuttle, fast forward, andreverse. The actuator creates detents on a frame-by-frame basis for theshuttle function and hard stops for fast forward and reverse.

[0045] The foregoing description of the preferred embodiments of theinvention has been presented only for the purpose of illustration anddescription and is not intended to be exhaustive or to limit theinvention to the precise forms disclosed. Numerous modifications andadaptations thereof will be apparent to those skilled in the art withoutdeparting from the spirit and scope of the present invention.

That which is claimed:
 1. A device comprising: a manipulandum; a brakesurface; an actuator configured to bring said manipulandum and saidbrake surface into contact.
 2. The device of claim 1, wherein saidactuator comprises an electromagnetic actuator.
 3. The device of claim1, wherein said actuator comprises a piezo-electric actuator.
 4. Thedevice of claim 1, wherein said piezo-electric actuator comprises: abase; a piezo-ceramic material having an outside edge surrounding acentral portion and connected to said base at said outside edge; and alever having a first end, a second end, and a flexure between said ends,said first end connected to said piezo-ceramic material at said centralportion and said second end connected to said braking surface.
 5. Thedevice of claim 1, wherein said actuator comprises an actuator incommunication with one of said manipulandum and said brake surface. 6.The device of claim 1, wherein said manipulandum comprises a scrollwheel.
 7. The device of claim 1, wherein said manipulandum comprises ascroll drum.
 8. The device of claim 1, wherein said manipulandumcomprises a linear slider.
 9. The device of claim 1, wherein said brakesurface comprises a disk.
 10. The device of claim 1, wherein said brakesurface comprises a conical braking surface.
 11. The device of claim 1,wherein said brake surface comprises a rectangular surface.
 12. Thedevice of claim 1, wherein said brake surface comprises a rounded edgefor contacting said manipulandum.
 13. The device of claim 1, whereinsaid brake surface is attracted to said manipulandum upon actuation ofsaid electromagnetic actuator.
 14. The device of claim 1, wherein saidbrake surface is repelled towards said manipulandum upon actuation ofsaid electromagnetic actuator.
 15. The device of claim 1, furthercomprising a position sensor in communication with said manipulandum.16. The device of claim 1, further comprising a controller incommunication with said electromagnetic actuator.
 17. The device ofclaim 16, further comprising a position sensor in communication withsaid controller.
 18. The device of claim 1, further comprising a springin communication with said manipulandum and said braking surface andconfigured to exert a force to separate said manipulandum and saidbraking surface.
 19. The device of claim 1, further comprising a leverin communication with said electromagnetic actuator and with one of saidmanipulandum and said brake surface.
 20. The device of claim 19, whereinsaid lever comprises a flexure.
 21. A computer-readable medium on whichis encoded computer program code for handling computerized requestscomprising: program code for determining when a haptic effect isprovided; program code for generating a signal to provide said hapticeffect, wherein said effect is provided by causing an actuator to bringa manipulandum and a brake surface into contact; and program code forsending said signal to said actuator.
 22. The computer-readable mediumof claim 21, further comprising computer code for receiving an inputsignal.
 23. The computer-readable medium of claim 22, wherein said inputsignal comprises position sensor data.
 24. The computer-readable mediumof claim 21, wherein said actuator comprises an electromagneticactuator.
 25. The computer-readable medium of claim 21, wherein saidactuator comprises a piezo-electric actuator.
 26. The computer-readablemedium of claim 21, wherein said actuator comprises an actuator incommunication with one of said manipulandum and said brake surface. 27.The computer-readable medium of claim 21, wherein said manipulandumcomprises a scroll wheel.
 28. The computer-readable medium of claim 21,wherein said manipulandum comprises a scroll drum.
 29. Thecomputer-readable medium of claim 21, wherein said manipulandumcomprises a linear slider.